admin login error. Get simple 3.0 (SOLVED)

[blackmoor77]

Hi, I'm new here and I tried to look for an answer, but didn't get any useful info...

So here is my problem:

After successful installation I logged into admin section, made some new pages, installed plugins etc... Then i left my computer and came back after two or three hours. I tried to login again but the CMS redirects me to admin login page. I don't get any "wrong password" -message or anything like that.

Code:

www.domain.com/folder/admin/index.php?redirect=/folder/admin/pages.php

If I enter wrong password then I get an error message...

So does anybody know the solution for this? I have tried to install GetSimple CMS three or four times and same error pops up everytime!

Please help.